Modern C++ Programming Cookbook

How to do it...

To conditionally compile portions of code, use the #if, #ifdef, and #ifndef directives (with the #elif, #else, and #endif directives). The general form for conditional compilation is as follows:

    #if condition1       text     #elif condition2       text     #elif condition3       text     #else       text     #endif

To define macros for conditional compilation, you can use either of the following:

• A #define directive in your source code:

        #define DEBUG_PRINTS         #define VERBOSITY_LEVEL 5

• Compiler command-line options that are specific to each compiler. Examples for the most widely used compilers are as follows:
  • For Visual C++, use /Dname or /Dname=value (where /Dname is equivalent to /Dname=1),

for example, cl /DVERBOSITY_LEVEL=5. 

• • For GCC and ...